Bushings for router bit storage.

[Chris Rosenberger]

I am making a new storage shelf for router bits. I started trying to layout the bits for 1/4" & 1/2" shanks. I decided to just drill all of the holes 1/2" & then use 1/2" X 1/4" bushings for the 1/4" bits.
I bought some of these bushings several years ago. I can not remember were I got them & cannot find source for them.
Anyone know of a seller for these?

[Noah Katz]

Not specifically, but I'd try McMaster